I have written an article about internal linking and its effects on Google Page Rank. I think it will be helpful to people when deciding how to lay out their sites to maximize the distribution of PR across their pages in their domain. Let me know what you think. It can be found here
"Page Rank is a system for ranking web pages used by the Google search engine. It uses the Internet's link structure to determine the relevency of sites and can result in higher listings in search engine results. " Hmmm.....I believe that Page Rank doesn't have anything to do with relevency and higher listings in SERPs.
When Google ranks a search it takes PR into account. If I do a search for "widgets" Google uses PR as a parameter to rank that page. It isn't the only factor, but an important one